From that point of view, you are right. But we have to think about solutions, as for example, you can not enter the same game (using this command) when a friend is in it.Even if you aren't in a party, your friend can use /fmsg to tell you to come into your game and help them find other players that are there. Wether you are in a party or not, your friend can still message you if they are in a solo game and could ask you to help them anyways, so that doesn't really solve the issue. Regardless of the possible positive uses of this command, for every time someone uses it for it's actual purpose, many more would be using it for different reasons and it would be impossible to control that.
Remember that to end problems, not only have to think about them, if you do not have to think about solutions.